1. Field of the Invention
The present invention relates to compositions useful in the application of colored cosmetics to the human body.
2. Background of the Art
The application of decorative or masking colors to the skin of humans and particularly to the face of humans is a highly specialized technical area. Compositions vary greatly depending upon the specific location to which the color is to be applied. The compositions used to apply color to the lips (e.g., lipstick or lip balm) require water repellancy because of their repeated contact with liquids. Mascara must have very high color density and strong bonding ability to eyelashes. Rouge, blusher and pancake must be very fine and easily spreadable. Eye shadow must also be fine and spreadable, yet should not break down during mild abrasion as.is encountered with repeated blinking and movement of the eyelids. There are also bases and foundations for colors which require specific properties to enable them to perform their unique function.
In recent years, styles have become more dramatic, allowing the use of more color and even multiple colors in the applications of makeup. For example, one portion of an eyelid may be pink and another portion blue. The change in colors can be used not only for the multicolor appearance, but the change can give an appearance of eyes being farther apart or closer together then they actually are. Such makeover techniques are highly valued by the cosmetician and makeup artist.
There are some problems involved in blending colors, however. Even though separate color sources and separate brushes may be used to apply the individual colors, the later applied colors will always contact the first applied colors. The brushes will then pick up colorant from the skin and transport it back to the color source. The brushes themselves will also retain mixtures of colors, rendering them less useful. The intermixing of colors in the original source will of course diminish the quality of the colorant.
It is fairly common to find encapsulated liquid materials in the marketplace. Technology has been available for many years to effectively provide microcapsules with liquid oleophilic ingredients. Representative processes are shown in U.S. Pat. Nos. 3,016,308 and 3,516,941. These patents disclose in situ polymerization reactions in which a hydrophobic oil phase is dispersed in an aqueous phase containing resin precursors, particularly aminoplast resin precursors (to form urea/aldehyde resins and the like). High shear agitation is used to keep the capsule size small. Addition of an acid catalyst initiates the polycondensation of the aminoplast precursors, resulting in the deposition of the aminoplast resin about the dispersed droplets of the oil phase. This produces the microcapsules.
Other polycondensation encapsulation techniques are shown in U.S. Pat. Nos. 3,429,827 and 4,000,087. These particular techniques are more limited in the classes of hydrophobic inner phases acceptable in the microcapsules because of reaction with the oil soluble monomer or poor solubility of the monomer in the desired hydrophobic phase.
U.S. Pat. No. 3,930,101 teaches that, to be retained in the hydrophobic phase during high shear dispersion of a fluid particulate dispersion, it is necessary that the particulate be preferentially wetted by the hyrophobic phase. It is suggested to use suitable surfactants which adsorb to the particulate surface as a way to achieve the desired preferential wetting. It has, however, been recognized that, in the in situ polymerization of aminoplast resins method for encapsulation, the presence of surfactants interferes with the deposition of the aminoplast resin at the hydrophobic phase/water phase interface, giving poorly formed or leaky capsules. Similarly, oil soluble suspending agents could alter the wetting of many particulates. Since many of these materials contain carboxylate groups, exposure to highly acidic medias often converts them to carboxylic acid groups altering their adsorbability to the particulates.
U.S. Pat. No. 4,307,169 teaches the inclusion of magnetic materials into a pressure fixable core material within a shell formed by interfacial polycondensation.
U.S. Pat. No. 3,954,666 teaches the preparation of semipermeable microcapsules containing catalysts and ferromagnetic materials.
U.S. Pat. No. 4,450,221 teaches magnetic toners comprising lyophilic magnetic particles and a resin surrounded by a resin wall to form microcapsules. Colorants such as pigments or dyes may be included in the wall forming resin or the toner. The magnetic particles are rendered lyophilic by treatment with a titanate or silane coupling agent. The coupling agent is said to uniformly disperse the particles in the binder resin and firmly bond the magnetic particle to the resin.